《Cracking the Coding Interview》——第17章：普通题——题目2

 1 // 17.2 Write an algorithm to check if someone has won the tic-tac-toe game.
 2 // Here is the game:
 3 //    xo-
 4 //    ox-
 5 //    --x
 6 // ‘x‘ won the game.
 7 // Rule: anyone who gets three consecutive pieces in a row, a column or a diagonal line first wins.
 8 #include <cstdio>
 9 using namespace std;
10 
11 int check(int a[][3])
12 {
13     if (a == nullptr) {
14         return -1;
15     }
16     
17     int i;
18     for (i = 0; i < 3; ++i) {
19         if (a[i][0] == a[i][1] && a[i][1] == a[i][2] && a[i][2] != 0) {
20             return a[i][2];
21         }
22         if (a[0][i] == a[1][i] && a[1][i] == a[2][i] && a[2][i] != 0) {
23             return a[i][2];
24         }
25     }
26     if (a[0][0] == a[1][1] && a[1][1] == a[2][2] && a[2][2] != 0) {
27         return a[2][2];
28     }
29     if (a[0][2] == a[1][1] && a[1][1] == a[2][0] && a[2][0] != 0) {
30         return a[2][2];
31     }
32     
33     return 0;
34 }
35 
36 int main()
37 {
38     int a[3][3];
39     int i, j;
40     
41     for (i = 0; i < 3; ++i) {
42         for (j = 0; j < 3; ++j) {
43             scanf("%d", &a[i][j]);
44         }
45     }
46     printf("%d\n", check(a));
47     
48     return 0;
49 }